This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. The postsynaptic density (PSD) is generally regarded the unit device that determines the structural and functional properties of a synapse. Among the many proteins that make up the PSD only a limited number has been characterized in great detail. The aim of this project is to identify novel PSD proteins and characterize their roles in synaptic formation, maintenance, and plasticity.